The following patent documents (gazettes) describe conventional techniques in this field:                Patent Document 1: JP-A No. 347246/1994        Patent Document 2: JP-A No.22794/1996        Patent Document 3: JP-A No.237231/1999        Patent Document 4: JP-A No.213427/1998        Patent Document 5: JP-A No.201919/1999        
A scanning electron microscope with a measurement function (hereinafter called a measurement SEM) has been used for control of semiconductor sample dimensions or other similar purposes. There are two dimensional measurement modes: a manual measurement mode and an auto measurement mode. In the manual measurement mode, an operator visually makes a measurement using a measurement cursor. In the auto measurement mode, a measurement SEM captures an image of a pattern to be measured (hereinafter called an “SEM image”) and creates, from the image, a line profile which is considered to reflect the cross section of the pattern; the position of an edge of the pattern is detected from the line profile and according to the detected edge, the measurement (length) of the pattern is calculated. In the auto mode, line profile creation, edge detection, and measurement calculation are carried out according to predetermined auto measurement parameters (hereinafter called AMP). Refer to Patent Document 1.
Patent Document 2 describes a groove shape measuring method in which a secondary electron image of a groove is obtained from observation of its surface by a scanning electron microscope and the width of the groove or track pitch as a groove shape factor is measured. This method comprises the following four steps. In the first step, the secondary electron image of the groove is converted into image file data in a sequential file form. In the second step, according to the image file data obtained in the first step, a profile image of contrast is obtained by successively scanning the number of “bright” spots existing in a measuring unit area enclosed by a desired length in the groove direction perpendicular to the groove width direction and a length in the width direction, equivalent to one dot as the minimum pixel unit. In the third step, for the profile image of contrast obtained in the second step, an edge detecting slice level for measurement of the opening width of the groove, HLV, and an edge detecting slice level for measurement of the bottom width of the groove, LLV, are calculated from the following equations, where AVG represents the average of the number of “bright” spots existing in each of the measuring unit areas:HLV=AVG×SLU(1<SLU<2)LLV=AVG×SLB(0<SLB<2)
In the fourth step, the track pitch between neighboring grooves is calculated using one of the edges of the groove opening or bottom which is detected according to the slice levels HLV and LLV calculated in the third step.
Patent Document 3 describes a method of determining the position of a pattern edge and Patent Document 4 and Patent Document 5 each describe a method of obtaining a line profile.
In recent years, there has been an increasing tendency to use an auto dimensional measurement method and the accuracy of auto measurement has been improving year by year. In auto measurement, there are two operation modes: a semi-auto mode in which movement to a measuring point or identification of a measuring point is done by an operator, and a full-auto mode in which measurements are made fully automatically, or with no operator assistance, by executing a recipe file which stores wafer surface data, measuring point position data or other information.
The recent trend is as follows: as semiconductor samples become smaller, measurement SEMs are more functional; they measure not only the line width of a pattern or the diameter of a hole automatically but also width roughness, edge roughness and so on for evaluation of the pattern shape.
In the conventional techniques, a set of auto measurement parameters (AMP) is needed to make a measurement for an item in the auto mode. Therefore, in semi-auto measurement, if several types of measurements are to be made, it is necessary to specify a set of AMP for each measurement type, which is very troublesome. In full-auto measurement, if several types of measurements are to be made, required AMP data is stored in a recipe file and thus operation is easy, but it is troublesome to revise and check the stored AMP data. A resulting measurement value is displayed in a window of the SEM upon execution of measurement; when several types of measurements are made, it is not easy to check numerical measurement values so the operator has to wait for completion of the whole measurement process until a list of measurement results appears.